There is a really interesting post on the history behind Mathematica, on Stephen Wolfram's
blog: There Was a Time before Mathematica …
Though I had used Mathematica only briefly and experimentally a while back, I had absolutely no
idea of its history.
Mathematica is a clever invention. My main exposure to what you might call mathematical programming
languages previously had been things like - for example - FORTRAN, APL - used in the fields of financial modelling, econometric modelling, weather system modelling, general mathematical programming/modelling (e.g., linear programming), and finite element analysis and mesh models. That is, nothing much like Mathematica.